Transient Stability Improvement by Using Static Synchronous Compensator

Abstract

Transient stability is the ability of power system to maintain synchronism when subjected to a severe disturbance such as three phase fault on transmission line or large increase in load or loss of large load. Static synchronous compensator (STATCOM) is one of the FACTS devices used to improve the transient stability of the power system. It regulates voltage at its terminal by controlling the amount of reactive power injected into or absorbed from power system. In this thesis the ability of STATCOM to improve the transient stability has been studied. Firstly two machine system under three phase fault is considered. The system is simulated using MATLAB/SIMULINK environment, then STATCOM of 200 MVA is implemented in the system to study its effect in improving the transient stability, after that the two machine system with step changing load is simulated in two steps without STATCOM and with STATCOM then the STATCOM damping characteristics have been analyzed. Secondly the study has been extended to a multi-machine system and IEEE 3-machine 9 bus system is taken as case study. The simulation is carried out using PSAT software. At the beginning the system has been simulated under fault and without STATCOM. Then STATCOM is installed in the system and its ability to enhance the transient stability has been investigated.